You literally imply there is one and describe it in the sibling comment reply.
Interestingly you present the possibility of a falsifiable hypothesis. Unfortunately due to the highly variable accuracy of diagnosis and propensity to treat (source: I was on The path to surgical training and now routinely diagnose appendicitis in my role as an emergency doctor) depending on health system capacity and availability to acute care the existing retrospective data doesn’t provide a satisfying result - what it does suggest is illuminating however; with a suggestion of a decrease in rate of incidence over the second half of the 20th century in industrialised countries, and a suggestion of increase in some developing countries. This would be more in keeping with an improvement in diagnostic capacity in both industrialised (less false positives) and developing (more false negatives) countries.